Related Experiment Video
Updated: Jul 19, 2026
07:14
Guided Endodontics: Three-Dimensional Planning and Template-Aided Preparation of Endodontic Access Cavities
Published on: May 24, 2022
A clinical method to determine the optimal apical preparation size. Part I
Roland Weiger1, Tibor Bartha, Matthias Kalwitzki
1Department of Periodontology, Endodontology and Cariology, School of Dental Medicine, University of Basel, Basel, Switzerland.
Summary
A new method helps determine optimal apical preparation size (APS) for root canals. Shaping canals to larger sizes than typically recommended ensures more complete preparation of canal walls.
Area of Science:
- Endodontics
- Dental Anatomy
- Root Canal Therapy
Background:
- Determining the optimal apical preparation size (APS) is crucial for effective root canal treatment.
- Current methods may not consistently ensure complete cleaning and shaping of the apical region.
Purpose of the Study:
- To introduce and validate a novel approach for determining the optimal apical preparation size (APS).
- To correlate a specific measurement with the required preparation size for complete root canal wall preparation.
Main Methods:
- Electronic working length (WL) was established in 212 root canals from 80 extracted molars.
- Special instruments determined the diameter (d(SI)) at WL where resistance was met.
- Root sections correlated d(SI) with potential rotary instrument diameters for complete wall preparation.
Main Results:
- Theoretically, APS of d(SI) + 0.60 mm achieved 98% circumferential apical preparations.
- Shaping to d(SI) + 0.40 mm (palatal/distal) resulted in 78% complete wall preparations.
- Shaping to d(SI) + 0.30 mm (mesial/buccal) resulted in 72% complete wall preparations.
Conclusions:
- The new approach effectively evaluates APS for most root canals.
- Current recommendations for root canal shaping may be insufficient; larger sizes are advised.
